/*
 * Copyright 2021 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "src/gpu/ganesh/GrMeshDrawTarget.h"

#include "src/gpu/BufferWriter.h"
#include "src/gpu/ganesh/GrResourceProvider.h"

uint32_t GrMeshDrawTarget::contextUniqueID() const
{
    return this->resourceProvider()->contextUniqueID();
}

template <typename W> static W make_writer(void *p, int count, size_t elementSize)
{
    // Don't worry about overflow in calculating byte size if 'p' is not null, presumably the actual
    // allocation validated it, so it should be safe after the fact.
    return p ? W{ p, count * elementSize } : W{};
}

skgpu::VertexWriter GrMeshDrawTarget::makeVertexWriter(size_t vertexSize, int vertexCount,
    sk_sp<const GrBuffer> *buffer, int *startVertex)
{
    void *p = this->makeVertexSpace(vertexSize, vertexCount, buffer, startVertex);
    return make_writer<skgpu::VertexWriter>(p, vertexCount, vertexSize);
}

skgpu::IndexWriter GrMeshDrawTarget::makeIndexWriter(int indexCount, sk_sp<const GrBuffer> *buffer, int *startIndex)
{
    void *p = this->makeIndexSpace(indexCount, buffer, startIndex);
    return make_writer<skgpu::IndexWriter>(p, indexCount, sizeof(uint16_t));
}

skgpu::VertexWriter GrMeshDrawTarget::makeVertexWriterAtLeast(size_t vertexSize, int minVertexCount,
    int fallbackVertexCount, sk_sp<const GrBuffer> *buffer, int *startVertex, int *actualVertexCount)
{
    void *p = this->makeVertexSpaceAtLeast(vertexSize, minVertexCount, fallbackVertexCount, buffer, startVertex,
        actualVertexCount);
    return make_writer<skgpu::VertexWriter>(p, *actualVertexCount, vertexSize);
}

skgpu::IndexWriter GrMeshDrawTarget::makeIndexWriterAtLeast(int minIndexCount, int fallbackIndexCount,
    sk_sp<const GrBuffer> *buffer, int *startIndex, int *actualIndexCount)
{
    void *p = this->makeIndexSpaceAtLeast(minIndexCount, fallbackIndexCount, buffer, startIndex, actualIndexCount);
    return make_writer<skgpu::IndexWriter>(p, *actualIndexCount, sizeof(uint16_t));
}
